Ipswich a week tomorrow with a one-point lead at the top of the table.
And a successful evening at Portman Road in front of the Sky cameras would strengthen their position ahead of the busy Christmas programme.
He said: "We have to learn from good and bad experiences, and as a team, we have learned and grown.
"This time last year we were probably wondering 'can we do it?'
"But now I think we have the belief that we are good enough to do it.
"That's not to say we will do it because there is still a long way to go, but we do believe in ourselves.
"I'd be telling you lies if I said I wasn't pleased with how we're doing at the moment.
"But we always want to do better, we are always looking for players to bring into the squad and will continue to do so.
"Being a successful football team is all about trying to improve, and I want the players already here to get better."
Goals from Nathan Ellington and Lee McCulloch saw off Gillingham, and while the result wasn't as emphatic as last week's drubbing of Preston, Jewell was just as pleased.
He said: "The dressing room was buzzing after the game and I told the lads it was a great one to win.
"If we are going to be serious contenders this season, we really have to win this sort of game.
"I think back to last season when Wimbledon beat us, and that was a result which cost us a place in the play-offs.
"We're still only midway through the season but this was a big result especially with the all the team around us winning.
"There's a few days break before our next game at Ipswich and it's nice to be going there on top of the league."
Jewell had words of consolation for Gillingham who he believes will be steered clear of the relegation zone by new boss Stan Ternent.
"I have to give credit to Gillingham who I thought were excellent, worked
extremely hard and made life every difficult for us," he said.
"It was one of our most
difficult games of the season so far, and if they continue like that, there is no danger of them going down.
"I spoke to Stan during the week and told him to take the job yesterday and not before, because I know he'd have them well-organised – he
didn't disappoint me.
"In the first half, I thought we played really well and our football was outstanding at times.
"But in the second half, Gillingham went for it a bit more, we had to dig deep and it wasn't as pretty to watch.
"We defended well from set-pieces, stuck our heads and bodies in the way, and got our rewards. admit I was relieved when Lee McCulloch knocked in the second goal at the end because we needed it.
"It was a great cross from Mike Flynn, even though I was screaming at him to stay in the corner to waste time!
"For the first goal, it was nice to see the strikers link up to score, and with our play in the first half, we could have had two or three more."
* Wednesday night's FA Youth Cup third round clash against Leeds has been switched to Elland Road in order to give the pitch at the JJB a break.